Glucose but not KCl diminishes submembrane granule turnover in mouse beta-cells
Glucose but not KCl diminishes submembrane granule turnover in mouse beta-cells
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DOI：
10.1530/jme-17-0063
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发表时间：
2017-10-01
影响因子：
3.5
通讯作者：
Rustenbeck, Ingo
中科院分区：
文献类型：
--
作者：
Brning, Dennis;Reckers, Kirstin;Rustenbeck, Ingo
KCL去极化被广泛用于模拟葡萄糖刺激的胰岛素分泌过程中的去极化。因此，氯化钾诱导的胰岛素分泌通常被认为等同于葡萄糖诱导的胰岛素分泌的第一阶段。在此，通过在原代小鼠胰岛细胞的TIRF显微镜下测量小鼠胰岛灌流后分泌、单个胰岛细胞内钙离子浓度和膜下胰岛素颗粒的迁移率来比较两种刺激的效果。使用了两种货物导向颗粒标记，即胰岛素-EGFP和C-肽-emGFP。用两者共有的颗粒行为来比较40 mM氯化钾和30 mM葡萄糖的顺序刺激和同样刺激的顺序刺激的效果。在细胞分泌反应的水平上，顺序脉冲方案根据两种刺激的顺序表现出显著的差异。KCL产生更高的最大分泌速率，并减弱对后续葡萄糖刺激的反应，而葡萄糖则增强对后续KCl刺激的反应。在颗粒行为水平上，在第一刺激阶段形成的差异在于，葡萄糖的颗粒总数、短期停留颗粒和到达颗粒都是颗粒周转的参数，显著小于KCl。这些在细胞分泌反应水平和膜下颗粒行为上的差异与相同的对KCl和葡萄糖刺激的初始反应机制是不相容的。
KCl depolarization is widely used to mimic the depolarization during glucose- stimulated insulin secretion. Consequently, the insulin secretion elicited by KCl is often regarded as the equivalent of the first phase of glucose- induced insulin secretion. Here, the effects of both stimuli were compared by measuring the secretion of perifused mouse islets, the cytosolic Ca2+ concentration of single beta- cells and the mobility of submembrane insulin granules by TIRF microscopy of primary mouse beta- cells. Two cargo- directed granule labels were used namely insulin- EGFP and C- peptide- emGFP. The granule behaviour common to both was used to compare the effect of sequential stimulation with 40 mM KCl and 30 mM glucose and sequential stimulation with the same stimuli in reversed order. At the level of the cell secretory response, the sequential pulse protocol showed marked differences depending on the order of the two stimuli. KCl produced higher maximal secretion rates and diminished the response to the subsequent glucose stimulus, whereas glucose enhanced the response to the subsequent KCl stimulus. At the level of granule behaviour, a difference developed during the first stimulation phase in that the total number of granules, the short- term resident granules and the arriving granules, which are all parameters of granule turnover, were significantly smaller for glucose than for KCl. These differences at both the level of the cell secretory response and granule behaviour in the submembrane space are incompatible with identical initial response mechanisms to KCl and glucose stimulation.